On Aug 25, 10:54*am, "Stormin Mormon"
wrote:
When the tel companies were deregulated, years ago. My Dad bought a little
book on phone wiring. I remember it saying 48 volts DC when the phone is not
in use "on hook" and about 5 volts DC when the phone is in use "off hook"..
90 VAC ring sounds correct.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Ralph Mowery" wrote in message

m...

Phones normally use just two wires. *Hook up the red and green wires and
forget the yellow.

Most of the time the phone wires will only have areound 12 volts on them.
While the phone rings there is around 90 volts on the line. *This voltage
probably will not kill you but it sure can be painful.

Those voltage numbers are tyoical and correct. Most telephone sytems
apply 48 volts DC to the line while waiting for a call to be made.
When the phone is 'off hook' (in use) a small portion of that 48 is
cross the phone, to activate the microphone in the handset etc. There
are a few systems (not common in North America or the UK) that used 24
volts. (Worked in the industry 1952 to 1992).

As mentioned ringing is AC (Alternating current) typically at around
20 hertz (cycles per second) compared to ouir regular electric supply
which is 60 hertz (In North America, but often 50 hertz elswhere!), at
around 90 volts. That can give a bit of a bite but not likely harm
you.

Assuming we are talking North American telephone systems; since it
isn't clear where the OP is located?

Yes; use the red and green wires to hook up the phone. If the added
phone does not ring (and you want it to) try hooking say the yellow
from the phone itself (not the yellow wire from the wall) to red or
the green and get somebody to call you. If that doesn't work you may
have to make a jumper change inside the phone itself; depending on
what model of the many thousands of phones that have been made!

Also make sure any jacks into which the phones plug are in nice dry
locations. Outside walls are not good places (in a cold climate
anyway) and some when they get damp can cause problems which can hold
up a telephone line and/or trip ringing before one answers. If wiring
is deteriorated replace it; nothing worse for both you and the telco.
of a faulty telephone line and if a problem is inside the house can be
costly in terms of a telco billing for trouble shooting it.